Optimization of sodium sulfide treatment of rice straw to increase the enzymatic hydrolysis in bioethanol production

The efficiency of sodium sulfide-assisted alkaline pulping for cellulose preparation from Oryza sativa L. rice straw in Vietnam for enzymatic saccharification was investigated. The response surface methodology was used for the determination of optimal technological parameters of alkaline pulping such as active alkali dosage, temperature and time. The optimal technological parameters were established to be active alkali dosage of 7%, treatment temperature of 100 °C and treatment time of 120 min. At these regimes, a maximal sugar yield of 51.8% (over dry rice straw) was obtained. It meant that the saccharification efficiency up to 97.1% could be achieved by using sodium sulfide-assisted alkaline pretreatment method. Addition of sodium sulfide into alkaline pretreatment resulted in higher sugar yield, higher level of depolymerization of lignin and less loss of cellulose. Moreover, liquid hydrolyzate after enzymatic hydrolysis was analyzed by HPLC to determine the compositions of sugar mixture. The fiber morphology in pretreated biomass solid was also revealed by SEM.     

Numerical simulation of hydrous transfer within fibrouscement slates

In situ distortion of fibrous-cement slates is brought about by exposure to different temperature and hygrometric gradients across the material. The aim of this research was to understand in detail the effect of each compositional change on the physical properties, and to use this knowledge for the manufacture of slates which would exhibit improved mechanical properties. A previous paper described the experimental measurements conducted to evaluate the impact of changing the composition of the slates on the physical properties controlling hydrous transfer. In the present paper, the physical parameters obtained from the experimental work are used in a numerical model. The numerical model, NSAT, employs a finite-element method to solve the non-linear diffusion equation. The numerical model was validated and subsequent simulations are described. A theoretical model has been obtained which shows good agreement between the results from practical tests at the experimental station and the predictions of the numerical model. The results also confirm the previous hypotheses of the industrial partner. The theoretical model obtained may be used for the prediction and specification of industrial materials having improved mechanical properties, and in particular, exhibiting less distortion.

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Résumé Les déformations locales dans les ardoises de fibrociment peuvent être engendrées par l'existence de gradients de température et d'hygrométrie au sein du matériau. Le but de ce travail est de comprendre en détail l'effet des modifications de composition des ardoises sur leurs propriétés physiques et d'utiliser ces connaissances dans la fabrication d'ardoises présentant de meilleures propriétés mécaniques. Un article précédent a décrit l'effet des traitements subis par les ardoises sur les paramètres physiques influant sur les transferts d'humidité. Dans cet article, les paramètres physiques sont utilisés dans un modèle numérique, NSAT. Le modèle numérique emploie la méthode des éléments finis pour résoudre l'équation non-linéaire de diffusion. D'abord le modèle numérique a été validé. Ensuite d'autres simulations plus complexes sont présentées. Les calculs numériques ont clairement mis en évidence les différents types de comportement de séchage qui correspondent aux diverses observations expérimentales du partenaire industriel. Le modèle numérique peut être utilisé pour la prévision et l'élaboration des matériaux industriels avec un meilleur comportement mécanique. En particulier, une dimunition de la déformation est attendue.

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Editorial note A. Raoof and T. H. Doan are working at the Laboratoire des Matériaux et des Structures du Génie Civil of LCPC, France, which is a RILEM Titular Member. A. Sabouraud is working at Pont-à-Mousson SA, France, which is a RILEM Titular Member.     

High-pressure nitrogen gas alloying of Fe-Cr-Ni alloys

The melting of Fe-Cr-Ni alloys under 200 MPa nitrogen pressure has shown that nitrogen significantly improves the mechanical properties. Tensile strengths of these high-nitrogen alloys were found to be proportional to interstitial nitrogen concentration. The tensile strengths of nitrogen-alloyed steels could be significantly increased over comparable carbon-alloyed steels. The increase in tensile strength was found to be proportional to the square root of the interstitial nitrogen concentration indicating that the strengthening may be controlled by thermal effects.     

Homer regulates the association of group 1 metabotropic glutamate receptors with multivalent complexes of homer-related, synaptic proteins

OBJECTIVE: The study aimed to assess the frequency, indications, and outcome of additional ocular procedures after initial treatment of vitrectomy (VIT) or tap-biopsy (TAP) for patients with endophthalmitis after cataract extraction. DESIGN: The study design was an analysis of observational data collected as part of a multicenter, randomized clinical trial. PARTICIPANTS: Of the 420 patients enrolled in the Endophthalmitis Vitrectomy Study, the 148 who had additional procedures were compared with the 272 who did not. MAIN OUTCOME MEASURES: The types, indications, and number of additional ocular procedures were assessed. A masked examiner measured visual acuity 9 to 12 months after study entry. RESULTS: Within 1 week of study entry, 8% of VIT eyes and 13% of TAP eyes underwent additional procedures, 14% for complications of the initial procedure and 86% for worsening ocular inflammation or infection. Cultures were obtained in 33 of the 38 eyes operated on for worsening inflammation or infection and were positive in 42%. Cultures obtained from the early additional procedures were positive more frequently in eyes with an initial TAP (71%) than in eyes with an initial VIT (13%). Both virulence of initial microbiologic organism isolated and poor presenting vision were risk factors for requirement of reoperation. In all cases in which a single organism was cultured at the initial procedure, when the reculture was positive, it was the same organism. Late additional procedures (after 7 days) were required in 27% of patients. Visual outcome was much worse for eyes that had an additional procedure compared to eyes that did not, and this was especially the case for eyes that had an early additional procedure. Only 15% of eyes that had an early additional procedure achieved 20/40 visual acuity as compared to 57% of eyes that did not. CONCLUSION: Need for an additional procedure was a marker of more severe disease, and patients who underwent additional procedures achieved poorer visual acuity at final follow-up.     

A simple method for the study of cytosolic content of oligonucleotides in cells

BACKGROUND: Nonuniform attenuation in the thorax can generate artifacts in single-photon emission computed tomographic myocardial perfusion studies that mimic coronary artery disease. In this article we present both phantom and simulation data, as well as clinical data, in support of an emission-based method that provides reliable correction for attenuation effects without the need for a transmission measurement. METHODS AND RESULTS: The attenuation map is derived from the measured distribution of 99mTc-labeled macroaggregated albumin in the lungs and a radioactive binder wrapped about the thorax. This information is acquired as part of a dual-isotope acquisition during the rest 201Tl study. Segmentation is used to define the interiors of lung and body compartments, which are assigned a single attenuation coefficient for each of the two tissue types. The appropriateness of this approach was investigated by examining the measured attenuation coefficients in a group of 80 individuals (40 male, 40 female) from positron emission tomographic transmission studies. The correction technique was evaluated with computer simulations, a physical phantom, and clinical data acquired from 20 patients. Analysis of the positron emission tomographic data found a small SD in the mean attenuation coefficients for the body (<5%) and lungs (<15%). The application of emission-based attenuation-correction technique produced a substantial reduction in the magnitude of the attenuation artifact in images obtained from both the phantom and the simulation studies. The emission-based attenuation-correction technique was easily applied to myocardial perfusion studies, where it had a significant effect, resulting in changes in interpretation for nine of 20 patients. CONCLUSIONS: The results of this study provide strong support for the concept that an attenuation map can be generated with fixed attenuation values in place of those that are directly measured. Thus the emission-based attenuation-correction technique can be considered an inexpensive alternative to transmission-based correction methods. Because the emission-based correction technique does not require any additional hardware, it has the major advantage of being applicable to all single-photon emission computed tomographic systems.     

Angiotensin II signal transduction pathways

It has been 100 years since the discovery of renin by Tigerstedt and Bergman. Since that time, numerous discoveries have advanced our understanding of the renin-angiotensin system, including the observation that angiotensin II is the effector molecule of this system. A remarkable aspect of angiotensin II is the many different physiological responses this simple peptide induces in different cell types. Here, we focus on the signal transduction pathways that are activated as a consequence of angiotensin II binding to the AT1 receptor. Classical signaling pathways such as the activation of heterotrimeric G proteins by the AT1 receptor are discussed. In addition, recent work examining the role of tyrosine phosphorylation in angiotensin II-mediated signal transduction is also examined. Understanding how these distinct signaling pathways transduce signals from the cell surface will advance our understanding of how such a simple molecule elicits such a wide variety of specific cellular responses.     

Parameters controlling topical delivery of oligonucleotides by electroporation

Multiple 5-hydroxytryptamine (5-HT) receptors have been identified (5-HT1A/1B/1D/1E/1F, 5-HT2A/2B/2C, 5-HT3A/3B, 5-HT4A/4B, 5-HT5A/5B, 5-HT6 and 5-HT7A/7B/7C/7D) and extensive evidence suggests that 5-HT receptors have a role in learning and memory. Indeed, available evidence strongly supports physiological, pathophysiological and therapeutic roles of 5-HT systems in cognitive processes, although the evidence seems incomplete. Indeed, there has been a clear tendency to use pre-learning administration most frequently, whereas post-learning and pre-retention administration protocols have been utilized in only a few studies, and probably this trend has led to missed relevant information. For instance, when pre- vs post-training administration of 5-HT1A agonist, 5-HT2 antagonists and 5-HT4 agonists have been compared contrasting findings were reported in aversive and appetitive learning tasks. Emerging evidence also indicates that 5-HT1A and 5-HT4 receptor agonists, as well as, 5-HT1A antagonists, 5-HT2 antagonists, 5-HT3 antagonists and 5-HT uptake inhibitors may have therapeutic utility in the treatment of Alzheimer's disease and amnesia. Inasmuch as the activation or blockade of diverse 5-HT receptors is able to modulate cognitive processes, and 5-HT uptake inhibition could have therapeutic applications in the treatment of cognitive disorders, it seems evident that the role of 5-HT in learning and memory is more complex than a simple imbalance. Consequently, the notion that activation of the 5-HT systems impairs performance, whereas reduced serotonergic function may facilitate learning, must be reconsidered.     

Optimal operation of transmission power networks by using improved stochastic fractal search algorithm

Neural Computing and Applications - This paper presents the application of an improved stochastic fractal search algorithm (ISFSA) for optimizing five single objectives of optimal power flow (OPF)...     

Maternal Undernutrition Modulates Neonatal Rat Cerebrovascular Structure,Function, and Vulnerability to Mild Hypoxic-Ischemic Injury via Corticosteroid-Dependent and -Independent Mechanisms

The present study explored the hypothesis that an adverse intrauterine environment caused by maternal undernutrition (MUN) acted through corticosteroid-dependent and -independent mechanisms to program lasting functional changes in the neonatal cerebrovasculature and vulnerability to mild hypoxic-ischemic (HI) injury. From day 10 of gestation until term, MUN and MUN-metyrapone (MUN-MET) group rats consumed a diet restricted to 50% of calories consumed by a pair-fed control; and on gestational day 11 through term, MUN-MET groups received drinking water containing MET (0.5 mg/mL), a corticosteroid synthesis inhibitor. P9/P10 pups underwent unilateral carotid ligation followed 24 h later by 1.5 h exposure to 8% oxygen (HI treatment). An ELISA quantified MUN-, MET-, and HI-induced changes in circulating levels of corticosterone. In P11/P12 pups, MUN programming promoted contractile differentiation in cerebrovascular smooth muscle as determined by confocal microscopy, modulated calcium-dependent contractility as revealed by cerebral artery myography, enhanced vasogenic edema formation as indicated by T2 MRI, and worsened neurobehavior MUN unmasked HI-induced improvements in open-field locomotion and in edema resolution, alterations in calcium-dependent contractility and promotion of contractile differentiation. Overall, MUN imposed multiple interdependent effects on cerebrovascular smooth muscle differentiation, contractility, edema formation, flow-metabolism coupling and neurobehavior through pathways that both required, and were independent of, gestational corticosteroids. In light of growing global patterns of food insecurity, the present study emphasizes that infants born from undernourished mothers may experience greater risk for developing neonatal cerebral edema and sensorimotor impairments possibly through programmed changes in neonatal cerebrovascular function.     

Effect of Addition Mode of Re in Bimetallic Pd–Re/TiO2 Catalysts Upon the Selective Aqueous-Phase Hydrogenation of Succinic Acid to 1,4-Butanediol

Hydrogenation of succinic acid aqueous solutions was performed using TiO₂-supported 2?wt% Pd and 2?wt%Pd?Cx?wt%Re catalysts, using either impregnation method or surface redox reduction of the monometallic catalyst. The former catalysts were superior in terms of activity and selectivity to 1,4-butanediol than the latter ones. However, higher Re loadings (3.4?C3.6?wt% compared to 0.6?C0.8?wt%) were necessary to initiate this synergy.